text: In chemistry, autoprotolysis is a chemical reaction in which a proton  is transferred between two identical molecules, one of which acts as a Brønsted acid, releasing a proton which is accepted by the other molecule acting as a Brønsted base. For example, water undergoes autoprotolysis in the self-ionization of water reaction. It is a type of molecular autoionization.
  Any solvent that contains both acidic hydrogen and lone pairs of electrons to accept  can undergo autoprotolysis.
  For example, ammonia in its purest form may undergo autoprotolysis: 
  Another example is acetic acid: